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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION IX AIR DIVISION

Technical Support Document 

for the

Gila River Indian Community Tribal Implementation Plan

___________________________________________________________

July 2010

Prepared by:

Sona Chilingaryan

Francisco Donez

Roger Kohn

Nicole Law

Al Petersen

Stanley Tong

Wienke Tax

Jerry Wamsley

Mae Wang

Joanne Wells
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Table of Contents

I. Introduction

II. Permit Requirements

III. Area Source Emission Limits

A. Open Burning

B. Fugitive Dust

IV. Generally Applicable Individual Source Requirements for Existing and New Sources

A. Visible Emissions

B. Volatile Organic Compound Storage, Usage, and Handling

C. Degreasing and Solvent Metal Cleaning

V. Source/Category-Specific Emission Limits for Existing and New Sources 

A. Secondary Aluminum Facilities

B. Aerospace Manufacturing

C. Nonmetallic Mineral Processing
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I. Introduction

Generally, the rules in a Clean Air Act (CAA) implementation plan must be 

enforceable (see section 110(a)) and must not relax existing plan requirements (see 

sections 110(l) and 193). Because there is no existing EPA-approved implementation 

plan in the Gila River Indian Community (GRIC) reservation, sections 110(l) and 193 do 

not apply to this action.

The GRIC reservation is located in south-central Arizona, adjacent to the Phoenix 

Metropolitan Area, in Pinal and Maricopa Counties. The entire reservation is 

designated attainment or unclassifiable/attainment for the following NAAQS 

pollutants: lead (Pb), carbon monoxide (CO), nitrogen dioxide (NO2), sulfur dioxide 

(SO2), particulate matter of 2.5 microns or less (PM2.5), and ground-level ozone. 40 

CFR 81.303. As such, for all of these pollutants, the requirements of part D, title I of 

the Act (e.g., RACT) do not apply in the GRIC reservation.

The only criteria pollutant for which a portion of the reservation is currently 

designated nonattainment is PM10. Approximately 92,000 acres of the GRIC 

reservation, along its northern boundary, lie within the Maricopa County (Phoenix 

Planning Area) serious PM10 nonattainment area. See 52 FR 29383, (August 7, 1987); 

61 FR 21372 (May 10, 1996) (reclassification to serious nonattainment effective June 

10, 1996). The remainder of the GRIC reservation is located in the portion of Pinal 

County that is currently designated as unclassifiable/attainment for PM10. 40 CFR 

81.303. The regulations in the TIP are enforceable and function independently of the 

PM10 nonattainment area requirements of subpart 4 of part D, title I of the Act. As 

such, the TIP regulations are reasonably severable from these part D requirements. 

40 CFR 49.7(c). Therefore, we are not evaluating the TIP for compliance with any 

part D requirements, such as the requirement for Best Available Control Measures 

(BACM) in CAA § 189(b). 

The following document provides USEPA Region 9’s evaluation of specific rules 

included in the GRIC’s Tribal Implementation Plan (TIP), which is codified in Title 18, 

Chapter 7 of the GRIC Code.

II. Permit Requirements

We are proposing to approve the minor source permit program in Part II as a base 

program suitable to the GRIC’s reservation, as discussed below. 

Program Summary

Part II of the TIP contains a permit program for minor sources that includes

requirements for preconstruction review, stack height limitations, continuous source 

emissions monitoring requirements, requirements for confidentiality of information, 

and permit fee provisions (Sections 1.0, 2.0, 4.0, 5.0, 6.0, 9.0, 10.0, 11.0). We are 

proposing to act only on those elements of Part II that constitute a minor source 
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permit program under CAA 110(a)(2)(C).

Program Evaluation

The minor source permit program sets forth legally enforceable procedures that 

enable the GRIC to determine whether the construction or modification of a facility, 

building, structure or installation, or combination of these will result in interference 

with attainment or maintenance of a NAAQS in the GRIC reservation or in a 

neighboring State, and includes the administrative procedures for making these 

determinations. The procedures enable the GRIC to prevent construction where such 

interference will occur. The procedures also require the GRIC to provide opportunity 

for public comment on information submitted by owners and operators, the GRIC’s

analysis of the effect of construction or modification on ambient air quality, and the

proposed approval or disapproval. The program identifies the GRIC DEQ as the agency 

which will be responsible for implementing these requirements throughout the 

reservation. These provisions meet the minimum requirements of 40 CFR 51.160-

51.163 as applied to the GRIC reservation and the particular mix of sources under the 

GRIC DEQ’s jurisdiction. For a more detailed explanation of the permit procedures

and air quality goals that the permit program addresses, see Letter dated June 22, 

2009, from Margaret Cook, Executive Director, GRIC DEQ, to Laura Yoshii, Acting 

Regional Administrator, EPA Region 9, “Re: Technical Corrections to the GRIC Air 

Quality Management Plan,” enclosure entitled “Minor New Source Review 

Demonstration.” 

Section 6.0 contains requirements for continuous source emissions monitoring. These 

requirements are not fully equivalent to the provisions of 40 CFR part 51, appendix P

(“Minimum Emission Monitoring Requirements”), but they are generally consistent 

with appendix P requirements and acceptable for purposes of a minor source permit 

program. We are not proposing to approve these provisions as meeting the 

requirements of 40 CFR 51.165 or appendix P or for purposes of any other 

requirement applicable to major stationary sources. We provide recommendations 

for rule improvement further below.

Section 9.0 contains stack height provisions that require that “[t]he degree of 

emission limitation required of any source . . . for control of any

pollutant shall not be affected by so much of any sources stack height that

exceeds good engineering practice or by any other dispersion technique.” Before the 

GRIC DEQ issues a permit or permit revision to a source based on a good engineering 

practice (GEP) stack height that exceeds the height allowed under Section 9.0, GRIC 

DEQ must notify the public of the availability of the demonstration study and provide

an opportunity for a public hearing. These provisions meet the applicable 

requirements for stack height procedures in 40 CFR 51.164.

Finally, Sections 10.0 and 11.0 establish requirements for confidentiality of 

information and permit fees. CAA 110(a)(2)(C) and 40 CFR part 51, subpart I do not 

establish specific requirements for confidentiality of information or permit fees in a 
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minor source permit program. We conclude that these TIP provisions are acceptable.

Recommendations for Rule Improvement

 Per the GRIC DEQ’s request by letter dated June 22, 2009, EPA is not proposing to 

act on the waiver provision in section 4.4.B as part of the TIP. To avoid confusion, 

we recommend that the GRIC formally amend the AQMP to remove this provision 

under Tribal law as well. 

 Per the GRIC DEQ’s request by letter dated June 22, 2009, EPA is not proposing to 

act on the title V provisions of Part II as part of the TIP. To avoid confusion, we 

recommend that the GRIC formally amend the AQMP to remove all title V and 

major source provisions from Part II, so that it contains only those non-title V 

(minor source) permit requirements that are part of the EPA-approved TIP. This 

will require corresponding revisions to different sections of Part II, including the 

definitions in section 1.0 and the permit fee provisions in section 11.0.

 Section 1.0 defines “major modification” to include projects that are subject only 

to the GRIC’s minor NSR program (i.e., not to Federal major NSR requirements). 

We recommend using a different term to refer to modifications subject only to the 

GRIC’s minor NSR program, as this use of a Federally-defined term could cause 

confusion.

 Section 4.2 requires that the BRDT control standard apply to any “new non-title V 

source” that has a potential to emit (PTE) at least 75 tpy of any criteria pollutant, 

and to any modification project that results in a PTE increase of at least 25 tpy of 

any criteria pollutant. We recommend that the GRIC consider lowering the BRDT 

threshold for new sources, as a 75 tpy threshold may allow fairly large sources to 

avoid installing pollution controls during initial construction, which is generally the 

point at which a source can install controls most cost-effectively.

 Section 4.4.A.1 establishes a permit term of 5 years for non-title V permits. We 

note that although EPA’s title V regulations establish a 5-year term for title V 

operating permits, preconstruction permits generally should not expire. We 

recommend that GRIC consider removing this provision or adding an application 

shield provision (similar to the title V application shield) for sources that submit 

timely and complete renewal applications.

 The permit revision requirements in section 5.0 remain potentially confusing and 

EPA commits to work with the GRIC to clarify these provisions as soon as possible. 

For example, the relationship (if any) and distinctions between the “permit 

revision” requirements in section 5.1 and the “significant permit revision” 

requirements in section 5.5 should be clarified.

 Section 4.6.D appears to require the GRIC DEQ to hold a public hearing upon 

request. To avoid undue administrative burdens, we recommend that GRIC 

consider revising this provision to provide the GRIC DEQ with discretion to grant or 

deny a hearing request based on the level of public interest.

As to Section 6.0 (“Continuous Source Emissions Monitoring”), we have the following 

recommendations for rule improvement:
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 In Section 6.4 Minimum Specifications for Monitoring Equipment, in paragraph 

6.4.A.1 “the Administrator” in line 6 of this section (paragraph 1) should be 

“reference method.”

 In Section 6.4 Minimum Specifications for Monitoring Equipment, in paragraph 

6.4.A.1.b, we recommend GRIC add the phrase “Appendix B of 40 CFR Part 60” to 

the end of this subparagraph.

 In Section 6.4 Minimum Specifications for Monitoring Equipment, in paragraph 

6.4.B, calibration gases, “(as amended)” should be deleted and the relevant date 

inserted.

 In Section 6.4 Minimum Specifications for Monitoring Equipment, paragraph 6.4.C 

requires that CEMS for measuring opacity complete a minimum of one (1) cycle of 

sampling and analyzing for “each successive 6-minute period.” We recommend 

that GRIC revise this to require completion of a minimum of one cycle of operation 

(sampling, analyzing, and data recording) for “each successive 10-second period,” 

consistent with the requirements of section 3.4 of 40 CFR part 51, appendix P. 

 In Section 6.4 Minimum Specifications for Monitoring Equipment, in paragraph 

6.4.E on combined effluents, this paragraph should be revised to clarify that the 

effluent needs to be monitored at the point of discharge.

 In Section 6.4 Minimum Specifications for Monitoring Equipment, in paragraph 

6.4.F, “Zero and drift”, we recommend including certain language from EPA’s 40 

CFR part 51, Appendix P, Minimum Emission Monitoring Requirements, that has 

been omitted.

 In Section 6.5 Minimum Data Requirement, in paragraph 6.5.B the word “deleted” 

should be changed to “considered”, consistent with Appendix P.

 In Section 6.6, Data Reduction, in paragraph 6.6.A, the calculation of pollutant 

concentration and oxygen concentration in the flue gas should be made on a dry 

basis. The Director may approve an alternative procedure on a case by case basis 

for calculating on a wet basis.

III. Area Source Emission Limits

We are proposing to approve the emission limits for area sources in Part V of the GRIC 

TIP as meeting the enforceability requirements of CAA section 110(a)(2)(A), as 

discussed below. 

A. Open Burning

Rule Summary

Part V, Section 1.0 generally prohibits open burning but cites exceptions for certain 

types of fires that are authorized with a burn permit and exemptions for certain types 

of fires that do not require a burn permit.

Rule Evaluation
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The evaluation criteria are primarily a comparison of Part V, Section 1.0 to open 

burning regulations from the Arizona Administrative Code, Section R18-2-602 Unlawful 

Open Burning and rules from other air districts and the reasonableness of the 

exception or exemption in the GRIC area.

Rules used for comparison include Maricopa County Rule 314 and Pinal County Article 

8, Open Burning (3-8-700). Both of these rules have been approved into the Arizona 

SIP by EPA.

Upon review, we have determined that Part V, Section 1.0 contains specific, welldefined requirements that meet our enforceability criteria for approval. The rule 

provides adequate restrictions for open burning, identifies activities requiring a burn 

permit and activities that are exempt from the rule’s requirements, and does not 

allow for variations from the rule other than those specified in the exemptions. 

Recommendations for Rule Improvement 

The following revisions are currently not the basis for rule disapproval, but are 

recommended for the next time the rule is amended.

1. For clarity, add the definition for “Agricultural Burning” in Section 2.0. See 

definition in Pinal County regulation 3-8-700.B. (Definitions) for Agricultural 

Burning.

2. Review and expand list of prohibited materials (Section 3.3) as compared with 

lists found in other state and local rules. 

3. For permitted residential fires (Section 3.4 A), include a statement regarding 

the prohibition of burning residential trash or other prohibited materials along 

with burning of vegetation and yard waste. Also, include a statement that 

material must be generated only from that residential property. See definition 

of “Residential burning” in Pinal County Regulation 3-8-700 B.

4. For improved rule clarity on permitted commercial fires, distinguish between 

one-time commercial land clearing operations and commercial fires of 

vegetative waste such as leaves, lawn clipping, etc. See Pinal County 

Regulation 3-8-700, Section C. 2.a & d for example of separating the two 

different activities. 

5. Define “other large scale permitted fires” so it is clear what type of burning is 

allowed under this category (Section 3.4 B).

6. Include “commercial” in list of those needing to apply for burn permits (section 

4.1.A) since a burn permit for commercial burning is also required. 

7. To strengthen safety and burn control requirements for all burning (Section 4.1 

B.) add requirements that fire must be constantly attended with reasonable

control tool on hand and that the burn pit or pile be at least 50 feet from 

nearest other dwelling unit or structure. See Pinal County Article 8. Open

Burning Rule Section D. 5. Burn Management Provisions. 

8. To strengthen safety and burn control requirements, expand applicability of 

Section 4.1 C to agricultural burning, with the exception of permit fee, if fee is
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not applicable to agricultural burning. These requirements are typically applied 

to agricultural burning by other air district rules. 

B. Fugitive Dust

Rule Summary

Part V, Section 2.0 is designed to limit the emissions of fugitive dust or particulate 

matter from a variety of activities and sources such as construction sites, bulk 

material hauling, storage piles, and unpaved parking lots. Rule provisions include a 

20 percent opacity limit as well as specific control measures to reduce particulate 

matter emissions from covered activities. For most facilities, developing, 

implementing, and maintaining a dust control plan sufficient to meet the 20 percent

opacity limit will provide the means for demonstrating ongoing compliance. 

Rule Evaluation

Upon review, we have determined that Part V, Section 2.0 contains specific, welldefined requirements that meet our enforceability criteria for approval. The rule 

provides adequate test methods for compliance determinations, identifies activities 

that are exempt from the rule’s requirements, and does not allow for variations from 

the rule other than those specified in the exemptions. The rule also requires 

adequate recordkeeping for demonstrating compliance.

Specifically, we compared this rule with other fugitive dust rules incorporated into 

the California and Arizona State Implementation Plans such as San Joaquin Valley Air 

Pollution Control District Regulation 8 – Fugitive PM Prohibitions (adopted 8/19/04 

and 9/16/04) and Maricopa County Rule 310 – Fugitive Dust Sources (adopted 

2/16/2000). Part V, Section 2.0 most closely resembles Maricopa County Rule 310 in 

form and substance. We approved Maricopa County’s Rule 310 into the Arizona SIP in 

2002.

Recommendations for Rule Improvement

We have two suggestions for future revisions to the rule that do not affect our ability 

to approve the rule. First, the rule should add a provision requiring Title V facilities 

to keep records available for five years. Second, given that the rule allows for reestablishing vegetative cover as a permanent stabilization strategy, the rule should 

incorporate test methods for determining vegetative cover. 

IV. Generally Applicable Individual Source Requirements for Existing and New 

Sources
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We are proposing to approve the general prohibitory rules for existing and new 

sources in Part VI of the GRIC TIP as meeting the enforceability requirements of CAA 

section 110(a)(2)(A), as discussed below. 

A. Visible Emissions

Rule Summary

Part VI, Section 1.0 prohibits the discharge into the ambient air from any single 

source of emissions, other than uncombined water, in excess of 20 percent opacity.

Rule Evaluation

When compared with other local air district rules and the State of Arizona

Administrative Code, this rule utilizes the same 20 percent opacity limit for

discharges into the ambient air. The State’s 20 percent opacity limit can be found in 

Arizona Rules at R18-2-702(B). Maricopa County Rule 300 and Pinal County Rule 2-8-

300 also have a 20 percent opacity limit for visible emissions. This rule also specifies 

the EPA test method for compliance determinations, which makes it enforceable. The 

GRIC rule is useful in enforcement as a quick visual indication of compliance.

Recommendations for Rule Improvement 

The following revision is currently not the basis for rule disapproval, but is 

recommended for the next time the rule is amended.

1. The definition in Section 2.0 for Visible Emissions should be amended to include 

gaseous emissions in addition to particulate emissions, see San Joaquin Valley 

Unified Air District Rule 4101, Visible Emissions. 

2. Remove the definition for “Intermittent Source” and Compliance and Test 

Method 4.2 “Test Methods-Opacity of Visible Emissions from Intermittent 

Sources” since there is no separate opacity standard or exception for 

Intermittent Sources in the rule. 

3. Remove any exceptions that do not have a current operating source in the GRIC 

area. This will avoid confusion and improve clarity of requirements. 

 

B. Volatile Organic Compound Storage, Usage, and Handling

Rule Summary

Part VI, Section 2.0 limits the discharge from operations involving heat to 15 pounds 

per day per device or operations using non-complying solvents to 40 pounds per day 

per device. If these limits are exceeded, one must control emissions with at least 85 

percent overall efficiency. Certain control techniques are required for VOC 
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containment and disposal. Specifications are provided for the storage of VOC in tanks 

over 40,000 gallons and in tanks of 250 to 40,000 gallons. Specifications are provided 

for vapor collection and vapor disposal for loading of VOC with a throughput of over 

40,000 gallons per day or less than 40,000 gallons per day.

Rule Evaluation

The evaluation criterion is primarily a comparison to the limits, specifications, and 

control techniques used in other Districts for handling VOC.

Recommendations for Rule Improvement

Gasoline would be included in the definition of “VOC” given in the October 4, 2006 

version of the rule. However, it is not clear whether the rule applies to the loading 

and storage of gasoline. This should be made clear in order to improve clarity and 

enforceability.

C. Degreasing and Solvent Metal Cleaning

Rule Summary 

Part VI, Section 3.0 applies to all new and existing solvent cleaning operations using 

volatile organic compounds (VOC) for solvent cleaning, including cold cleaning 

degreasers, open-top vapor degreasers, and conveyorized degreasers. The rule 

exempts solvent cleaning operations regulated by another Section in Part VI, 

laundering and housekeeping supplies and activities, testing for surface cleanliness or 

the cleaning of laboratory equipment at a laboratory, and cleaning solutions 

containing twenty (20) percent or less VOC by either weight or volume. 

The rule includes equipment and operating requirements. Instead of meeting certain 

equipment requirements, operators of open-top vapor degreasers and conveyorized

degreasers are allowed to meet the standards of the rule through the use of an 

Emissions Control System (ECS). Owners or operators of solvent cleaning businesses 

that were in operation on or after November 1, 2004 are required to submit an 

Operation and Maintenance (O & M) Plan for the ECS. 

Rule Evaluation 

The Bluebook (Issues Relating to VOC Regulation Cutpoints, Deficiencies, and 

Deviations, EPA, May 25, 1988) and the Little Bluebook (Guidance Document for 

Correcting Common VOC & Other Rule Deficiencies, EPA Region 9, August 21, 2001) 

were used to help evaluate the rule for enforceability. 

In addition, EPA’s Control of Volatile Organic Emissions from Solvent Metal Cleaning 

(November 1977) and the California Air Resources Board’s (CARB) Determination of 

Reasonably Available Control Technology and Best Available Control Technology for 
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Organic Solvent Cleaning and Degreasing Operations (July 18, 1991) were used to 

evaluate rule stringency. 

Recommendations For Rule Improvement

The following revision is currently not the basis for rule disapproval, but is 

recommended for the next time the rule is amended.

Section 6.1(E) allows the owner or operator of a conveyorized degreaser to meet the 

requirements of Section 6.1 by operating an ECS in accordance with Section 7 of the 

Rule. Section 7, however, does not specify an overall control efficiency for the ECS. 

Specifying an overall control efficiency could improve both the rule’s stringency and 

enforceability. For example language, see Maricopa Rule 331 Appendix IV. 1.

V. Source/Category-Specific Emission Limits for Existing and New Sources 

We are proposing to approve the source category-specific emission limits for existing

and new sources in Part VII of the GRIC TIP as meeting the enforceability 

requirements of CAA section 110(a)(2)(A), as discussed below. 

A. Secondary Aluminum Facilities

Rule Summary

Part VII, Section 1.0 covers all new, existing and modified secondary aluminum 

facilities located in the Gila River Indian Community. 

The rule incorporates by reference the requirements contained in 40 C.F.R. Part 63, 

Subpart RRR, National Emission Standards for Hazardous Air Pollutants (NESHAPs) for 

Secondary Aluminum Production. Subpart RRR contains emission limits for dioxins and 

furans and other hazardous air pollutants that may formed during the smelting of 

aluminum scrap. Subpart RRR also contains requirements for the testing, monitoring, 

recordkeeping, reporting, and labelling of process equipment used in the secondary 

aluminum production industry to ensure compliance with the regulations.

In addition to the requirements in Subpart RRR, GRIC’s rule sets a 20% opacity limit 

from any emission source and establishes that volatile organic compound (VOC) 

emissions be reduced by three (3) percent each year from an established baseline 

emission rate for a total of five (5) years. Future annual reductions are not required 

if a facility achieves the required 15%VOC reduction early. 

The rule requires any owner or operator using an emissions control system to reduce 

emissions, to submit to GRIC for approval, an operation and maintenance plan. The 

plan shall specify key system operating parameters such as temperatures, pressures, 

or flow rates necessary to determine compliance with the requirements. The plan is 

also required to contain detailed procedures to maintain emission control systems.
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The rule further requires facilities to install, maintain, calibrate, and operate 

monitoring devices for operations involved in incinerating, adsorbing, or otherwise 

processing organic materials. 

Rule Evaluation

The following criterion was used to evaluate the submitted rule. 

Enforceability - The Bluebook (Issues Relating to VOC Regulation Cutpoints, 

Deficiencies, and Deviations, EPA, May 25, 1988) and the Little Bluebook (Guidance 

Document for Correcting Common VOC & Other Rule Deficiencies, EPA Region 9, 

August 21, 2001) were used to help evaluate compliance with the CAA 110(a)(2)(A) 

requirement for enforceability. 

The submitted rule is more stringent than EPA’s National Emission Standard for 

Secondary Aluminum Production as it incorporates the national standard and adds 

additional requirements such as opacity limits and VOC reduction requirements for

secondary aluminum facilities. The monitoring, recordkeeping, reporting and other 

requirements generally ensure that the submitted rule can be enforced. 

GRIC submitted a technical support document (TSD) for this rule that was originally 

drafted in October 2000. As such, much of the discussion in GRIC’s TSD on the nonapplicability of the Secondary Aluminum NESHAPs to area sources and the application 

of the term “clean charge” are no longer correct. 

For example, the NESHAPs require secondary aluminum production facilities which 

melt non-clean scrap to conduct a dioxin/furan emissions test. This test is required 

whether or not a facility emits more than 10 tons of any single hazardous air pollutant 

(HAP) or 25 tons of any combination of HAPs, and is used to determine compliance 

with the NESHAPs’ dioxin/furan emission limit. GRIC’s TSD, however, states that one 

of their facilities, an extruder, is exempt from the NESHAPs because it is a minor 

source of HAPs (i.e., area source) and melts only clean charge.

Further, EPA has narrowly defined “clean charge” as “scrap known by the owner or 

operator to be entirely free of paints, coatings, and lubricants...” (40 C.F.R. 63.1503). 

A source test report from the facility indicated they purchase scrap with lubricants and 

melts that scrap into round ingots of various lengths and diameters. The extruder is 

not exempt from the NESHAPs because it melts scrap which does not meet the 

NESHAPs definition of “clean charge”.

Because GRIC’s rule incorporates the Secondary Aluminum NESHAPs as published in the 

July 1, 2006 version of Title 40 of the Code of Federal Regulations, Part 63, subpart 

RRR, EPA did not rely on those portions of GRIC’s TSD written in 2000 that differ from 

the NESHAPs. The other portions of GRIC’s TSD provide useful background information 

on the aluminum industries in Gila River.
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Recommendations for Rule Improvement

The following rule improvements are provided for evaluation.

Reporting and recordkeeping requirements. Paragraph 2.2 requires facilities to 

demonstration annually by February 15, that VOC emissions were reduced by at least 

three percent of the VOC baseline emission rate. The rule should clarify whether the 

demonstration is to be submitted to the GRIC or provided upon request.

Section 4 on recordkeeping should clarify how long records should be maintained. 

Consistent with CAA Title V and the federal statute of limitations, we recommend 

that records be maintained for five years. 

B. Aerospace Manufacturing

Rule Summary 

Part VII, Section 2.0 controls VOC emissions from aerospace manufacturing or rework 

facilities within the exterior boundaries of the Gila River Indian Community.

This rule establishes VOC emission limits on primers, topcoats, chemical milling 

maskants, and specialty coatings. As an alternative to meeting the applicable coating 

limits set forth in the rule, the owner or operator may comply by operating an 

emission control system with a combined VOC emission capture and control efficiency 

of at least 81% by weight. 

Another alternative to meeting the coating limits is using the averaging provision 

stated in section 4.1.A. The averaging provision can only be used with coatings listed 

in table 1 of the rule (categories of primers, topcoats, and maskants) and cannot be 

used in specialty coating categories (section 5.2). EPA has assumed the averaging 

period to be 30 days because section 4.1.A describes monthly records and section 5.1 

discusses a monthly mass-weighted average. Also, we have inferred from section 5.1 

that the equation to determine compliance would be similar to those in South Coast 

Air Quality Management District (SCAQMD) Rule 1113 in Appendix A and Bay Area Air 

Quality Management District (BAAQMD) Rule 8-32 Manual of Procedures, Volume I 

Procedure 6.

In order to demonstrate compliance with the averaging provision, it is also necessary 

to keep appropriate and accurate records as listed in Section 4.1.A. The facility shall 

maintain a list of coatings used. The list must contain the category of the coating, 

noncompliant compounds, VOC content as applied, and monthly usage amount. When 

using the averaging provision, additional information such as the calculation records 

should also be retained. 
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Rule Evaluation 

The Bluebook (Issues Relating to VOC Regulation Cutpoints, Deficiencies, and 

Deviations, EPA, May 25, 1988) and the Little Bluebook (Guidance Document for 

Correcting Common VOC & Other Rule Deficiencies, EPA Region 9, August 21, 2001) 

were used to help evaluate the rule for enforceability. The monitoring, 

recordkeeping, reporting and other requirements generally ensure that the submitted 

rule can be enforced. 

We have also considered the guidance document Improving Air Quality with Economic 

Incentive Programs (“EIP”, EPA, January 2001) in evaluating the averaging provision in 

section 5.1. We have identified several elements of Section 5.1 that are inconsistent 

with EPA’s EIP guidance and have discussed them briefly below in the section 

describing recommendations.

The Control Techniques Guideline for the Control of Volatile Organic Compound 

Emissions from Coating Operations at Aerospace Manufacturing and Rework 

Operations (Aerospace CTG) EPA/OAQPS December 1997 was used to evaluate the 

rule’s stringency.

Recommendations for Rule Improvement

The following revisions are currently not the basis for rule disapproval, but are 

recommended for the next time the rule is amended.

Section 1.2 – The rule has several exemptions that are not recommended in the 

Aerospace CTG. The CTG does not list "chemical milling," "electrodeposition," 

"composite processing," "electronic parts and assemblies," "manufacture of aircraft 

transparencies," and "wastewater treatment operations" as exemptions. Also, 

exemptions such as "metal finishing" and "manufacturing and rework of parts and 

assemblies not critical to the vehicle's structural integrity or flight performance" seem 

broad and may make the rule difficult to enforce. Removing some or all of these 

exemptions, or defining them more narrowly, will improve enforceability and may 

result in additional emission reductions.

Section 3.1 – Emission limits are consistent with the Aerospace CTG, but do not 

approach those achieved by SCAQMD Rule 1124 and other analogous state and local 

rules. More stringent emission limits could help further reduce emissions from 

aerospace manufacturing and rework operations. 

Section 3.4 – The rule allows for other coating application methods not listed in this 

section, as long as they achieve emission reductions equivalent to high volume low 

pressure (HVLP) or electrostatic spray applications techniques. To strengthen the 

enforceability of this provision, an additional test method should be added to 

determine transfer efficiency. An example of such a test method is the SCAQMD 
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method "Spray Equipment Transfer Efficiency Test Procedure for Equipment User, May 

24, 1989."

Section 5.1 – Table 1 limits are allowed to average across coatings (primer, topcoat 

and maskants) to comply with limits on a monthly basis. The following 

recommendations to improve the enforceability of rule are based on guidance in the 

Little Bluebook and the EIP document.

 The rule should include the calculation procedures (usually in the form of an 

equation) for determining compliance with the rule.

 Depending on the calculation procedure, the monitoring, recordkeeping, and 

reporting provisions may need to be revised to ensure that the rule requires 

recordkeeping sufficient to determine compliance. 

 The rule should specify the averaging period, justify the averaging period, and 

demonstrate that the averaging period is consistent with attaining, maintaining 

the NAAQS, meeting progress requirements, and ensuring equivalency with RACT. 

Averaging Times for Compliance with VOC Emission Limits – SIP Revision Policy, 

memo from John R. O’Connor, EPA/OAQPS, January 20, 1984 has more details on 

what information is necessary when justifying an averaging period longer than 24 

hours.

 To improve the environmental benefits achieved by the rule, we suggest setting 

the emissions limitation at 90% of what otherwise would have been the limit 

without averaging.

 The rule should specify that if there is a violation of the averaging provision, each 

and every day within the averaging period is a separate violation. I.e., unless 

otherwise demonstrated, a violation of a 30-day averaging provision results in 30 

separate violations.

C. Nonmetallic Mineral Processing

Rule Summary 

Part VI, Section 3.0 controls volatile organic compound (VOC) emissions from cutback 

asphalt and particulate matter emissions (PM-10) from sand and gravel facilities. 

Rule Evaluation 

The Bluebook (Issues Relating to VOC Regulation Cutpoints, Deficiencies, and 

Deviations , EPA, May 25, 1988) and the Little Bluebook ( Guidance Document for 

Correcting Common VOC & Other Rule Deficiencies, EPA Region 9, August 21, 2001) 

were used to help evaluate the rule for enforceability. The monitoring, 

recordkeeping, reporting and other requirements generally ensure that the submitted 

rule can be enforced.

A part of the Gila River Indian Community is a serious PM-10 non-attainment area. 

Sand and gravel facilities operate in this portion of the Gila River Indian Community. 

We are proposing to treat the nonattainment area requirements of part D, title I of 
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the Act as not applicable to the TIP because the TIP (including its rules) are 

reasonably severable from part D requirements. We note, however, that this rule 

does not meet BACM since it is less stringent than several analogous rules in other 

areas, including South Coast Rule 1157 and Maricopa County Rule 316. See the 

“Additional Recommendations” section below for examples of how analogous rules are 

more stringent. 

Recommendations for Rule Improvement

The following revisions are currently not the basis for rule disapproval, but are 

recommended for the next time the rule is amended:

 Unlike SCAQMD Rule 1157 and Maricopa Rule 316, Section 3 does not contain 

requirements for storage piles, unpaved roads and track out.

 Unlike SCAQMD Rule 1157, Section 3 does not contain a prohibition for any visible 

fugitive dust plume to exceed 100 feet in any direction from any activity, 

equipment, storage pile or disturbed surface area. 

 Unlike Maricopa County Rule 316, Section 3 does not require watering systems be 

operated in order to maintain a 4% minimum moisture content. 

 We note that the applicability section of the rule refers to the use of cutback 

asphalt and VOC limits, but that the rule appears generally to regulate PM

emissions from nonmetallic mineral mining and processing operations. We 

recommend clarifying the scope and applicability of this rule.